Green nanoparticle synthesis has been achieved using the extracts of leaves/stem/roots of mimosa (Mimosapudica) as the reducing and capping agent. The study utilizes the highly pernicious and otherwise worthless terrestrial weed mimosa. Nanoparticles were rapidly synthesized at ambient temperature and shape/size control was made possible by controlling the extract: metal proportions. The results of UV-visible spectrophotometric, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy support the biosynthesis and characterization of the nanoparticles. One of the distinguishing features of the study is that it employs the whole plant unlike most previous studies which are confined to the use of leaves.